I had the same problem. Didn’t get an error or anything. I managed to get it to work by removing the last character from my password. NOTE: I didn’t change my password on the website, I just didn’t type the last character into the client.
I stumbled onto this fix while testing the problem. I was trying to see if I could get a “Wrong Password” message.
I’m not sure why it worked, the last character of my password was an “&”, so maybe the client has a problem with some special characters.
Don’t know if that’s any help to you, but I thought it’s worth mentioning.
So it seems like the WhatPulse client cannot handle “&” symbols in passwords. (The website seems to handle them correctly)
I think you may have made up that statistic, most of the sites that I use accept special characters. If a site is storing passwords ‘properly’, eg. using a secure salted hash, then it shouldn’t matter what characters are in the password. It annoys me when sites impose restrictions like alphanumeric characters only.